The invention relates to a change-speed gearbox providing three forward gear ratios and one reverse gear ratio wherein the gears in the gearbox are in three gear planes and the clutches are generally in one gear plane to reduce the axial length of the gear box. The invention is an improvement over the gear box described in Austrian pat. No. 51,824.
The present invention concerns a change-speed gearbox comprising an input drive shaft, and a coaxially arranged output shaft able to be coupled with it, and a number of non-coaxial counter shafts. A number of groups of meshing gear wheels are mounted on these shafts. For changing gear there are sliding clutches with interlocking engagement means. One of the change-speed clutches is available for directly coupling the output shaft with the input shaft. Each of the other clutches may be used for connecting a gear wheel with the shaft on which the gear wheel is bearinged so that in each case only those pairs of gear wheels are effective which in view of their diameter (and the number of teeth dependent on the diameter) are to be used for producing the desired transmission ratio.
Besides the coaxially arranged input and output shafts the prior change-speed gearbox has three counter shafts. The gear wheels are divided up into four groups so that there are thus four gear wheel planes, that is to say two front and two rear gear wheel planes. The clutches are all arranged in the center part of the gearbox, that is to say essentially in a so-called clutch plane placed between the second and third gear wheel planes. In connection with this known design attempts have already been made to make a compact design. However, the gearbox still had a comparatively long overall length because, as noted, four gear wheel planes are needed.